Hello
Thank you for posting in Microsoft Community forum.
You may have three options:
- Demote and reinstall the machine OS that were disconnected and re-promote it.
- Use the "repadmin /removelingeringobjects" tool to remove inconsistent deleted objects and then resume replication.
- Resume replication. Inconsistent deleted objects may be introduced.
If you must need to bring it back online, please check if there are lingering objects on the Domain Controller with a Tombstone Lifetime that has exceeded, if so, you can try to remove them or make them to replicate to other online DCs. For more information, please refer to similar thread below.
Prblems with DC Replication - Microsoft Q&A
I hope the information above is helpful.
If you have any question or concern, please feel free to let us know.
Best Regards,
Daisy Zhou